I've traveled to a few remote locations with mission teams. These villages are so far back in the bush, or up the mountain, or away from any cities that they seldom see visitors, don't have electricity, and therefore have few of the basics which we count on in the West. This sometimes makes it a challenge to know what our team might best do. And then you get into questions of what to leave to help the lives of those we've spent some time with. We sometimes dig wells, establish medical clinics, and look for ways to enhance the education of children & teens in the schools. We've also found another option thanks to a friend in our church in Augusta.
His organization offers solar powered products including FM radio, audio Bible which uses solar but also has a hand crank generator recharge, an "all in one" unit, and they continue to develop items of use to missionaries, mission agencies, and those that are served in remote areas around the world.
See Bob's work at http://www.the-ctc.org/products.htm